I'm also doing the same, but I'm getting hung up at the multiplayer section.
Following the tutorial to the letter leads to an error reading the mission files.
However, creating a folder named "mpmissions", (the tutorial just says to create "missions"), adding a folder inside there called "dayzOffline.chernarusplus" and copying a standard init.c from my "DayZServer" folder (where the tutorial suggests getting a copy of the ServerDZ.cfg file from) allows a multiplayer server to be created and be joinable following the rest of the steps.
Is this the correct way to create the multiplayer server in the article, and those steps have just been missed?
Tutorial: https://community.bistudio.com/wiki/DayZ:Modding_Basics